Step 1
Push down on the top roller to release it from the top track. Tilt the door forward, and lift the door off the bottom corner floor bracket.
Step 2
Remove the top roller by pulling it out of the door with your hands or a pair of pliers. An alternative removal method is to insert a flat-head screwdriver at the bottom lip of the top roller and push the roller down to lift it out of the hole.
Step 3
Take the top roller to a home improvement store or hardware store, and compare it to top rollers on the market. The replacement roller should look similar to the old roller. If, for example, the old roller is round, then the new roller should be round. If the old roller has a 7/16-inch base, then the new roller's base should be that measurement or close to that measurement.
Step 4
Push the new roller into the same hole from which you removed the old roller. It should fit snugly so it does not pull out easily. If necessary, use a hammer lightly to get the new roller in place. If the new roller is too wide for the hole, drill a bigger hole. If it is too small for the hole, fill the hole with wood putty, and drill a new hole about 1 inch to the side of the old hole. The roller’s label should direct you to the right drill bit size to use.